Water repellent wax coating offers eco-friendly breathability

The coating, developed by a team from Aalto University in Finland, uses carnauba wax, a substance used in medicines, foodstuffs, plus the surface treatment of fruits and car waxes.

During the processing, the wax is thawed and decomposed in water into wax particles that are anionic, like cellulose. For the wax particles to adhere well to the cellulose surface, a cationic substance is needed as a buffer, since the oppositely charged particles attract one another. In previous studies, a natural protein called polylysine was used for this.

“Polylysine is very expensive so in our current study, it's been substituted with a much cheaper, cationic starch that's already commercially available,” said Aalto University PhD student Nina Forsman.

According to Aalto University, cationic starch is not quite as effective as polylysine, but two layers of the starch mixed with two wax particles are enough to make the textile waterproof.